Help me in solving FCTRL problem

My issue

My code

#include <iostream>
using namespace std;

long long int factorial(int n){
     long long int f=1;
    for(int i=1; i<=n; i++){
        f=f*i;
    }
    return f;
}

int main() {
	// your code goes here
	int t;
	cin>>t;
	while(t--){
	    
	    int N;
	    cin>>N;
	    long long  int z=factorial(N);
	    int c=0, bit=0;
	    while(!bit){
	        bit=z%10;
	        z=z/10;
	        if(bit==0){
	            c++;
	            
	       }
	       else{
	           bit=1;
	       }
	       
	        
	    }
	    cout<<c<<endl;
	    
	}
	return 0;
}



Problem Link: FCTRL Problem - CodeChef